Surface chemical properties of typical commercial coal-based activated cokes were characterized by Xray photoelectron spectroscopy(XPS) and acid-base titration, and then the influence of surface chemical properties on...Surface chemical properties of typical commercial coal-based activated cokes were characterized by Xray photoelectron spectroscopy(XPS) and acid-base titration, and then the influence of surface chemical properties on catalytic performance of activated cokes of NO reduction with NH3 was investigated in a fixed-bed quartz micro reactor at 150 ℃. The results indicate that the selective catalytic reduction(SCR) activity of activated cokes with the increase of its surface acidic sites and oxygen content,obviously, a correlation between catalytic activity and surface acidic sites content by titration has higher linearity than catalytic activity and surface oxygen content by XPS. While basic sites content by acid-base titration have not correlation with SCR activity. It has been proposed that surface basic sites content measured by titration may not be on adjacent of acidic surface oxides and then cannot form of NO2-like species, thus the reaction of reduction of NO with NH3 have been retarded.展开更多
Surface chemical properties of soil colloids are the important factor affecting soil fertility and genesis. To provide scientific basis for soil genetic classification, promotion of soil fertility and reasonable ferti...Surface chemical properties of soil colloids are the important factor affecting soil fertility and genesis. To provide scientific basis for soil genetic classification, promotion of soil fertility and reasonable fertilization, the specific surface area and electric charge of soil colloids in relation to clay minerals and organic matter are further discussed on the basis of the results obtained from the studies on surface chemical properties of soil colloids in five main soils of China. Results from the studies show that the effect of clay minerals and organic matter on the surface chemical properties of soil colloids is very complicated because the siloxane surface, hydrated oxide surface and organic matter surface do not exist separately, but they are always mixed together and influenced each other. The understanding of the relationship among clay minerals, organic matter and surface chemical properties of soil colloids depends upon further study of the relevant disciplines of soil science, especially the study on the mechanisms of organo-mineral complexes.展开更多
Zinc-ion capacitors(ZICs),which consist of a capacitor-type electrode and a battery-type electrode,not only possess the high power density of supercapacitors and the high energy density of batteries,but also have othe...Zinc-ion capacitors(ZICs),which consist of a capacitor-type electrode and a battery-type electrode,not only possess the high power density of supercapacitors and the high energy density of batteries,but also have other advantages such as abundant resources,high safety and environmental friendliness.However,they still face problems such as insufficient specific capacitance,a short cycling life,and narrow operating voltage and temperature ranges,which are hindering their practical use.We provide a comprehensive overview of the fundamental theory of carbon-based ZICs and summarize recent research progress from three perspectives:the carbon cathode,electrolyte and zinc anode.The influence of the structure and surface chemical properties of the carbon materials on the capacitive performance of ZICs is considered together with theoretical guidance for advancing their development and practical use.展开更多
Two variable charge soils were incubated with biochars derived from straws of peanut, soybean, canola, and rice to investigate the effect of the biochars on their chemical properties and Pb（II） adsorption using batc...Two variable charge soils were incubated with biochars derived from straws of peanut, soybean, canola, and rice to investigate the effect of the biochars on their chemical properties and Pb（II） adsorption using batch experiments. The results showed soil cation exchange capacity （CEC） and pH significantly increased after 30 d of incubation with the biochars added. The incorporation of the biochars markedly increased the adsorption of Pb（II）, and both the electrostatic and non-electrostatic adsorption mechanisms contributed to Pb（II） adsorption by the variable charge soils. Adsorption isotherms illustrated legume- straw derived biochars more greatly increased Pb（II） adsorption on soils through the non-electrostatic mechanism via the formation of surface complexes between Pb（II） and acid functional groups of the biochars than did non-legume straw biochars. The adsorption capacity of Pb（II） increased, while the desorption amount slightly decreased with the increasing suspension pH for the studied soils, especially in a high suspension pH, indicating that precipitation also plays an important role in immobilizing Pb（II） to the soils.展开更多
基金the High Technology Research and Development Program of China(No.2011AA060803)the Beijing Key Laboratory Annual Program(No.Z121103009212039)
文摘Surface chemical properties of typical commercial coal-based activated cokes were characterized by Xray photoelectron spectroscopy(XPS) and acid-base titration, and then the influence of surface chemical properties on catalytic performance of activated cokes of NO reduction with NH3 was investigated in a fixed-bed quartz micro reactor at 150 ℃. The results indicate that the selective catalytic reduction(SCR) activity of activated cokes with the increase of its surface acidic sites and oxygen content,obviously, a correlation between catalytic activity and surface acidic sites content by titration has higher linearity than catalytic activity and surface oxygen content by XPS. While basic sites content by acid-base titration have not correlation with SCR activity. It has been proposed that surface basic sites content measured by titration may not be on adjacent of acidic surface oxides and then cannot form of NO2-like species, thus the reaction of reduction of NO with NH3 have been retarded.
文摘Surface chemical properties of soil colloids are the important factor affecting soil fertility and genesis. To provide scientific basis for soil genetic classification, promotion of soil fertility and reasonable fertilization, the specific surface area and electric charge of soil colloids in relation to clay minerals and organic matter are further discussed on the basis of the results obtained from the studies on surface chemical properties of soil colloids in five main soils of China. Results from the studies show that the effect of clay minerals and organic matter on the surface chemical properties of soil colloids is very complicated because the siloxane surface, hydrated oxide surface and organic matter surface do not exist separately, but they are always mixed together and influenced each other. The understanding of the relationship among clay minerals, organic matter and surface chemical properties of soil colloids depends upon further study of the relevant disciplines of soil science, especially the study on the mechanisms of organo-mineral complexes.
文摘Zinc-ion capacitors(ZICs),which consist of a capacitor-type electrode and a battery-type electrode,not only possess the high power density of supercapacitors and the high energy density of batteries,but also have other advantages such as abundant resources,high safety and environmental friendliness.However,they still face problems such as insufficient specific capacitance,a short cycling life,and narrow operating voltage and temperature ranges,which are hindering their practical use.We provide a comprehensive overview of the fundamental theory of carbon-based ZICs and summarize recent research progress from three perspectives:the carbon cathode,electrolyte and zinc anode.The influence of the structure and surface chemical properties of the carbon materials on the capacitive performance of ZICs is considered together with theoretical guidance for advancing their development and practical use.
基金supported by the Key Technoligies R&D Program of China during the 12th Five-Year Plan period (2012BAJ24B06)the National Natural Science Foundation of China (41230855)
文摘Two variable charge soils were incubated with biochars derived from straws of peanut, soybean, canola, and rice to investigate the effect of the biochars on their chemical properties and Pb（II） adsorption using batch experiments. The results showed soil cation exchange capacity （CEC） and pH significantly increased after 30 d of incubation with the biochars added. The incorporation of the biochars markedly increased the adsorption of Pb（II）, and both the electrostatic and non-electrostatic adsorption mechanisms contributed to Pb（II） adsorption by the variable charge soils. Adsorption isotherms illustrated legume- straw derived biochars more greatly increased Pb（II） adsorption on soils through the non-electrostatic mechanism via the formation of surface complexes between Pb（II） and acid functional groups of the biochars than did non-legume straw biochars. The adsorption capacity of Pb（II） increased, while the desorption amount slightly decreased with the increasing suspension pH for the studied soils, especially in a high suspension pH, indicating that precipitation also plays an important role in immobilizing Pb（II） to the soils.
